Adapter for semiautomatic radiotelegraph key



L. M. TEMPLE March 4, 1969 Sheet INVENTOR. LEMUEL M. EMF/.5 MM

1.. M. TEMPLE 3,431,354 ADAPTER FOR SEMIAUTOMATIC RADIOTELEGRAPH KEYMarch 4, 1969 Sheei Filed Oct. 22, 1965 2 ma w N w BE A W. m 1 w L S w AM e I United States 3,431,354 ADAPTER FOR SEMIAUTOMATIC RADIOTELEGRAPHKEY Lemuel M. Temple, Stratton Mountain Road, West Wardsboro, Vt. 05360Filed Oct. 22, 1965, Ser. No. 501,381 US. Cl. 178-82 4 Claim Int. Cl.H04l15/08, 27/00: H04!) 1/04 This invention relates to radiotelegraphkeys of the semiautomatic type used in keying a signal-producing circuitto transmit intelligible code signals; and it is more particularlydirected to an adapter for such keys which will permit them to operateas so-called fully automatic keys.

semiautomatic keys employing a mechanical vibrator, such as a weightedleaf spring pendulum, have long been used by telegraph operators for theproduction of dot" pulses automatically in forming code characters. Asis well known, the paddle of such semiautomatic key is simply movedlaterally to one side from a central or rest position to produce the dotpulses, and to the opposite side of that central position to produce adash. Separate sets of keying contacts are employed in producing the dotpulses from those producing the dash? pulses. Because of the vibratormechanism, the set of keying contacts used for producing the "dot pulsesare cyclically opened and closed as long as the paddle is held by theoperator in the dot position, within the limits of the mechanicalvibrator. However, when the paddle is moved to the opposite or dash"position, the other set of keying contacts is closed and held closed aslong as the paddle is held in the dash" position. Thus the operator, inmaking two or more dashes in forming a code character, must manuallyrelease the paddle and again return it to the dash position in order toform more than one dash" pulse. Hence the designation of semiautomatickeyer" for this type of device, since each dash" pulse must be formedmanually.

There are, of course, fully automatic keying devices available in whichboth dash as well as dot pulses are formed automatically, simply byshifting a paddle or keying member from one position to another from acentral or neutral position. Generally these fully automatic keyers areelectronic devices employing either vacuum tubes or semiconductors andare relatively complicated mechanically and electronically, resulting insubstantial investment in equipment.

It is accordingly an object of this invention to provide an adapter forthe conventional semiautomatic mechanical key or bug, as it is sometimesreferred to, in order to render it capable of fully automatic operation.It is a further objectto do this without impairing the normalfunctioning of the semiautomatic key or bug, or requiring any majormodification of it, so that the bug may be immediately restored to itsconventional semiautomatic operation merely by throwing a switch.

As a further object of the invention, provision is made for modifyingthe automatic dash forming capability of the adapter device so that theoperator may manually select either of two diflerent modes of operation.In one mode, the device automatically completes the last dash pulse inany series of dashes, irrespective of the fact that the key paddle maybe released to neutral position prior to the completion of such terminaldash pulse. In the other mode of operation, the device provides manualcontrol of the length or period of the last dash in a series. Suchlatter mode of operation enables the operator more easily to move from adash producing condition to a "dot producing condition, and back again,without the terminal dash of a proceding group overtaking a succeedingdot or dots, which would of course result in gar- Patented Mar. 4, 1969bling the code character attempted to be formed. The in terposition ofone or more dots between dashes in a code character when an operator isfirst learning to use a fully automatic key, is particularly difiicultuntil he has developed skill and timing by experience. In order tofacilitate the learning process and to enable an inexperienced operatorto transmit intelligible code characters at reasonably rapid speeds, thefeature provided by the present invention of manually controlling theterminal dash pulse is accordingly especially advantageous.

Another object of the present invention is to provide an adapter devicewhich is of small, simple mechanical construction and size, such that itmay be easily afixed to a standard semiautomatic key and form a partthereof, without cluttering the operating table with accessoryequipment.

These and other objects and advantages of the present invention areillustrated by the device and circuits shown in the accompanyingdrawings and described hereinafter. It is of course understood that thespecific mechanical construction and particular circuit arrangementshereindescribed are by way of illustration rather than limitation of theinvention which is defined in the accompanying claims.

In the drawings:

FIG. 1 is a perspective view of a conventional semiautomatic key with anadapter unit of the present invention attached thereto;

FIG. 2 is a schematic diagram of a semiautomatic key and the adapter;

FIG. 3 shows a modified circuit for the adapter; and

FIG. 4 illustrates a still further modification of the basic circuitdesign. I

The arrangement whereby the adapter unit is physically attached to aconventional semiautomatic key is illustrated in FIG. 1, wherein the key10 is provided with an outboard chassis or adapter unit 12 suitablysecured along one edge of the key base, serving to house and support theseveral components incorporated in the adapter unit. Attachment ofadapter 12 to the base of key 10 may be accomplished in any suitablemanner, such as by means of machine screws 14 passing through theadapter unit 12 into the base of the key, or by means of bus bars 15used for electrical connections as described below. For purposes ofconvenience of illustration and description here, key 10 and adapterunit 12 are shown as provided with corresponding external pairedterminals 16-16, 18-18, 20- 20", each pair of which is joined by a bus15. Again for purposes of convenience of description, terminals 16-16are referred to hereinafter as the common or ground terminals foradapter 12 and key 10, respectively; terminals 18-18 are termed the dot"terminals of the adapter and key, respectively; and terminals 20-20 arehereinafter termed the dash terminals of the adapter and key,respectively. It will of course be understood that this specificarrangement of the terminals is not necessary and, in fact, in mostinstances the members comprising such terminals will be located withinthe chassis of adapter 12 and within the base of key 10, and connectingleads run between them so that there is no external exposure of suchterminals or leads.

Key 10 is provided with a pair of terminals and as sociated pairedconductors 22 for connection to the circuit to be keyed. Adapter 12 issupplied with low voltage through a power cord 24 for operating a relay26 forming part of the adapter unit. The adapter is further providedwith variable resistors 28, 30. Resistor 28 controls the length orperiod of each dash pulse, while resistor 30 controls the speed at whichthe combination of key and adapter produces dash pulses automatically.In addition, the adapter unit includes manually controlled switches 32,34, 36; switch 32 being used to turn on'the power supply, switch 34serving to provide optional modes of automatic dash formation by theadapter and switch 36 being used to connect the adapter into the keyedcircuit or to return the key to its normal operating condition.

As is well known, such semiautomatic keys are operated by manuallymoving a central key or paddle member 38 horizontally to the left orright of a central or neutral position to which it is normally biased.Moving paddle 38 to the right sets in motion a type of spring leafvibrator which carries an electrical contact which is intermittentlybrought into engagement with a stationary insulated contact so long asthe paddle is held in the dot forming position, within the limits ofcourse of the period of vibration of which the key is capable. Suchintermittent closing of this set of contacts, hereinafter re ferred toas the dot forming contacts 19-19, completes the circuit through pairedconductors 22 and produces corresponding pulses in the keyed circuit.Thus the operator is relieved of the task of forming each dot pulseseparately in transmitting code characters. When paddle 38 is moved inthe laterally opposite direction, a second set of contacts 2121',hereinafter referred to as the dash contacts, is closed. These dashcontacts are in electrical parallel with the dot" contacts and in thenormal function of the semiautomatic key the operator must manually formthe dash pulses of the code characters being transmitted by moving thepaddle 38 to and releasing it from the dash position. As has been aboveindicated, however, with the provision of the adapter unit 12 hereindisclosed, the operator is relieved of the necessity for forming aseries of dashes manually, as the adapter unit takes over this functionand performs it automatically so long as the paddle 38 is held in thedash forming position.

Turning now to a consideration of the arrangement for accomplishing thisobjective, one form of adapter circuit is illustrated in FIG. 2 of theaccompanying drawings wherein it is shown schematically connected to key10.

The relay of the adapter includes an energizing coil 40 operating anarmature 42 which normally makes contact with relay contact 44 but whichis moved to an alternate position making contact with relay contact 46when relay coil 40 is energized. Armature 42 is permanently connected tothe ground or common terminal 16, and also the B position of switch 34.The relay circuit of the adapter further includes a time-delay networkcomprising a capacitor 48, and the variable resistors 28, 30 previouslymentioned. Variable resistor 30 is connected in parallel across thecombination of resistor 28 and coil 40. Capacitor 48, in turn, isconnected directly across resistor 30 when switch 34 is in the Aposition, whereas the capacitor circuit, when switch 34 is in the Bposition, includes the dash contact-s 2121' of key 10.

Switch 36 merely serves to insert the adapter unit 12 into the keyingcircuit when moved to the B position, or to restore the key to itsnormal operating condition when switch 36 is in the A position.

In the conventional key, keying contacts 19 and 21 are normallyconnected in parallel by an internal conductor, indicated at 50 indotted lines in FIG. 2, and to the ungrounded conductor of the keyedcircuit 22. It is accordingly necessary to remove or disconnectconductor 50 of the key when attaching adapter 12.

The operation of the device as illustrated in FIG. 2 occurs as follows.Adapter 12 is connected into the circuit of key by moving switch 36 tothe B position, and to a suitable power source, such as battery 52, byclosing switch 32. Assume first that switch 34 is in the A position, inwhich condition the adapter is arranged to complete the last dash in aseries of such dashes automatically, irrespective of the opening of thekey by the operator prior to the normal termination of such final dash.

When paddle 38 of key 10 is moved to the dash position, closing contacts2121', relay coil 40 is energized by completion of the circuit from thepositive side of battery 52 through the relay coil 40, through switch36, dash contacts 2121', the common or ground terminals 1616', armature42 and contact 44 to the negative side of the battery. Since condenser48 is connected across energizing coil 40 of the relay, the condenser isalso charged when paddle 38 of key 10 is moved to the dash position. I

Energizing of relay 26 causes armature 42 to break contact with relaycontact 44 and to make contact with relay contact 46. This thencompletes a circuit between the dot terminals 1818 and the common orground terminals 16-16, thereby producing a pulse in a keyed circuit 22.By reason of the resistor-capacitor network in the relay circuit, thecharge accumulated by the condenser holds the relay closed momentarily,depending upon the resistance and capacitance values of the components.In a typical circuit employing a relay of 5,000 ohms resistance,suitable values for resistors 28, 30 are 10,000 ohms each, with acapacitor 48 having a value of 16 mfd. When the capacitor is discharged,relay 26 will again open and armature 42 will return to its initialposition making contact with relay contact 44. If paddle 38 of key .10is still held in the dash position by the operator, then the foregoingsteps are repeated and a second dash pulse is produced in the keyedcircuit 22, and this cycle of operation continues until the key isopened.

Key 10 in the circuit of FIG. 2 continues to operate in its normalmanner when paddle 38 is moved to the dot forming position, in that thecyclical closing of contacts 19-19 takes place as before to produce dotpulses in the keyed circuit.

In the condition of the circuit just described, wherein switch 34 is inthe A position, the terminal dash, in a series of dash pulsesautomatically produced, takes the same time interval as the precedingdash pulses, regardless of the fact that the operator may have openedkey 10 before that last dash is completed. In other words, the terminaldash in a series of such dashes is completed automatically regardless ofthe fact that the operator may release the key prematurely. This mode ofoperation is referred to as self-completing mode of automatic dashformation.

In, order to permit an operator to employ a mode of operation in whichhe controls, or at least is able to shorten, the time period of theterminal dash in a series, switch 34 is switched to the B position. Whenthe system is so used, an operator may then deliberately shorten theterminal dash in a series, and this will help an inexperienced operatorin learning to use the key. The short ening of the dash may be almostimperceptible, but is sufficient to provide a better opportunity for theinexperienced telegrapher to insert a dot in the code character beingtransmitted without being overtaken by a following dash. As mentionedabove, this condition is likely to occur when the system is operated inthe self= completing mode by an inexperienced operator.

In the non-completing mode of operation, since switch 34 is in the Bposition, the discharge of condenser 48 does not take place directlythrough energizing coil 40 of the relay but instead is completed throughthe dash contacts 2121' of key 10. Thus if key 10 is opened, the holdingcircuit for the relay is interrupted and the relay immediately returnsto its normal position.

A modification of the foregoing circuit is shown in FIG.. 3. This isessentially similar to that of FIG. 2 except for the inclusion of diodes52, 54 in connection with switch 34. Diode 54 is placed in seriesbetween position B of' the switch and armature 42 of the relay 26 toallow cur rent to flow from capacitor 48 to armature 42 but not in theopposite direction. Diode 52 is connected between the A and B positionsof switch 34 in a direction to allow current to flow from A to B but notin the reverse direction.

This arrangement is useful in permitting a lower im= pedance relay to beused than is needed in the circuit of FIG. 2, and in this mannerreducing the expense of the adapter unit. Unless the energizing coil 40of the relay has a sufficiently high impedance and high mechanicalsensitivity, the keyed circuit may be adversely affected when using thecircuit shown in FIG. 2. However, by means of the blocking arrangementprovided by diodes 52 and 54 in the circuit of FIG. 3, this problem isavoided and a lower cost relay may then be satisfactorily employed.

Another modification of the circuit is shown in FIG. 4 in whichprovision is made for controlling an external circuit concurrently withthe operation of the key, for such purposes as operating a toneoscillator for monitoring transmission, or to serve as a break-in switchfor transferring a single antenna from .a receiver to the transmitterwhenever the key is closed, or for providing an isolated keying circuitfor the transmitter instead of the normal key contacts of thesemiautomatic key itself. The circuit of FIG. 4 is essentially the sameof that of FIG. 3 except for the inclusion of an additional switch 38,.and a second armature 56 and contacts 58, 60. Armature 56 and itsassociated contacts are electrically insulated from armature 42 and itscontacts in the relay assembly. Armature 56 and relay contacts 58, 60are connected, respectively, to terminals 62, 64 .and 66 for control ofany external circuit as mentioned above. If armature 56 is employed foractually keying the transmitting circuit, the keyed circuit would becompleted through terminals 62 and 66 upon energization of relay 26. Insuch a circuit, therefore, both the formation of dot pulses as well asdashes must be accomplished by means of the relay and further revisionof the circuits previously described is therefore necessary in theconnections made between the adapter 12 and key 10.

As mentioned above, the circuit of FIG. 4 incorporates an additionalsingle-pole double-throw switch 38. The pole of this is connected to aterminal 39 from which a bus bar 15' leads to terminal 18' of the key.Lead 17 from the ungrounded side of the keyed circuit is run directly toterminal 18 of the adapter instead of to terminal 18' of the key asbefore. The switch 38 contacts for the A and B positions of switch 38are connected, respectively, to terminals 18 and 20 of the adapter unit.

To operate the circuit of FIG. 4 as a fully automatic system in which aremote or separate circuit is keyed by armature 56 through terminals 62,66 of the adapter, each of switches 34, 36, 38 is placed in the Bposition. If it is desired to operate the system in the same manner asthat of FIG. 3, then switch 38 is moved to its A position, in whichcondition dash pulses are made automatically by the adapter unit whilethe dot pulses are made directly by the key. And finally, if the adaptercircuit is to be bypassed entirely and the key operated in its originalmanner, then switches 36 and 38 are both moved to their A positions.

The arrangement of FIG. 4 provides maximum flexi- 'bility of control andaffords ease of operation for a semiautomatic key of an order notheretofore realizable.

What is claimed is:

1. In a device for adapting a semiautomatic radiotelegraph key to enableit to be used in producin dash pulses automatically in a keyed circuitas well as the dot pulses of which it is regularly capable, thecombination which comprises a mounting member having thereon a dotterminal,

a dash terminal and a common or ground terminal, each of which hasprovision for electrical connection to corresponding terminals of thekey, and power terminals for connection to a source of electric power;

a relay and switch means operated thereby carried by said mountingmember, said switch means having a normally biased position in which itcompletes a first Ercuit between ground and one of said power terminalsand being operable by said relay to break said first circuit andcomplete an alternate circuit between ground and said dot terminal;

a relay-energizing circuit connected between the other of said powerterminals and said dash terminal and adapted to be completed by the keyin dash position, said energizing circuit including the operating coilof said relay, said energizing circuit also including a time-delaynetwork to produce a momentary delay in the return of said switch meansto its normal position upon interruption of the relay-energizing circuitby the key.

2. A device as defined in claim 1, wherein said timedelay networkincludes a capacitor and manually controlled switch means, saidcapacitor being connected at one electrode to the other of said powerterminals, and alternative circuits selected by said manual switchconnecting the opposite electrode of said capacitor to said groundterminal and to said dash terminal.

3. A device as defined in claim 2, which further includes diode means insaid alternative circuits selected by Said manual switch, one such diodemeans connected in the circuit leading from the capacitor to said groundterminal to prevent current flow toward said capacitor, and another ofsuch diode means connected between the capacitor side of said firstdiode means and the circuit leading to said dash terminal to preventcurrent flow toward the latter.

4. In a semiautomatic telegraph keyer of the mechanical type having twosets of electrical contacts for producing, respectively, dot and dashelectrical pulses in an external circuit upon closing of the contacts ofthe respective sets by manual movement of a key member from a normalrest (no-contact-producing) position to either of two alternatepositions, whereby the dash contacts produce a continuouslyclosed-circuit condition when said key member is held in the dashposition and the dot contacts produce a series of interruptedclosed-circuit conditions when said key member is held in the dotposition,

the improvement which adapts said telegraph keyer automatically toproduce a series of interrupted circuit-closing conditions in the dashposition of the key member and comprises a mounting member havingthereon a dot terminal,

a dash terminal and a common or ground terminal, each of which hasprovision for electrical connection to corresponding terminals of thekey, and power terminals for connection to a source of electric power;

a relay and switch means operated thereby carried by said mountingmember, said switch means having a normally biased position in which itcompletes a first circuit between ground and one of said power terminalsand being operable by said relay to break said first circuit andcomplete an alternate circuit between ground and said dot terminal;

a relay-energizing circuit connected between the other of said powerterminals and said dash terminal and adapted to be completed by the keyin dash position, said energizing circuit including the operating coilof said relay, said energizing circuit also including a time-delaynetwork to produce a momentary delay in the return of said switch meansto its normal position upon interruption of the relay-energizing circuitof the key.

References Cited UNITED STATES PATENTS 2,235,627 3/1941 Boor. 2,302,29011/ 1942 Breedlove.

THOMAS A. ROBINSON, Primary Eran liner.

US. Cl. X.R. 178-66; 325-161

1. IN A DEVICE FOR ADAPTING A SEMIAUTOMATIC RADIOTELEGRAPH KEY TO ENABLE IT TO BE USED IN PRODUCING "DASH" PULSES AUTOMATICALLY IN A KEYED CIRCUIT AS WELL AS THE "DOT" PULSE OF WHICH IT IS REGULARLY CAPABLE, THE COMBINATION WHICH COMPRISES A MOUNTING MEMBER HAVING THEREON A "DOT" TERMINAL, A "DASH" TERMINAL AND A COMMON OR "GROUND" TERMINAL, EACH OF WHICH HAS PROVISION FOR ELECTRICAL CONNECTION TO CORRESPONDING TERMINALS OF THE KEY, AND "POWER" TERMINALS FOR CONNECTION TO A SOURCE OF ELECTRIC POWER; 